Which of the following is not considered a method of confinement?

The method described as plugging is primarily used to stop leaks by blocking openings where hazardous materials are escaping. This involves materials such as putty, mud, or other substances designed to seal leaks in storage tanks, drums, or similar containers. However, it does not fit the broader category of confinement methods, which typically aim to contain hazardous substances to prevent their spread rather than just address leaks.

In contrast, encapsulation, diking, and capping are methods specifically employed to contain hazardous materials. Encapsulation refers to covering hazardous materials with a protective layer to prevent exposure or further leakage. Diking is the process of creating barriers around a hazardous substance to prevent it from spreading into the surrounding environment, usually using earth or other materials to create a containment area. Capping involves placing a cover over a hazardous area to reduce exposure and limit the release of materials.

These methods share a common goal of ensuring that hazardous materials remain contained, mitigating the risk of exposure to people and the environment, which is why they are categorized as methods of confinement.